基于线粒体基因组序列对羊蛔虫的种系发育分析

Phylogenetic analysis of Ascaris ovis based on sequences of the mitochondrial genome

为了明确羊蛔虫的分类学地位，本研究首先对羊蛔虫的线粒体基因组全序列进行测定和分析，并基于其蛋白编码基因序列构建了种系发育关系。结果表明，羊蛔虫的线粒体基因组序列全长14288bp，编码36个基因，包括12个蛋白质编码基因（coxl-3、nadl-6、nad4L、atp6和cytb）、22个tRNA基因、2个rRNA基因和2个非编码区，其与人蛔虫和猪蛔虫的线粒体基因组核苷酸序列的相似性分别为98．7％和98．2％，种系发育树显示，羊蛔虫、人蛔虫和猪蛔虫位于同一进化支，亲缘关系很近。这些研究结果提示羊蛔虫、人蛔虫和猪蛔虫可能属于同一物种。本研究为羊蛔虫在分类、演化、分子流行病学和控制等方面的基础研究提供了基本数据。

To ascertain the taxonomic status of Ascaris ovis, the complete mitochondrial （rot） genomic sequence of A. ovis was firstly sequenced and characterized in this study,and then phylogenetic relationships based on sequences of protein-coding genes was re-constructed. The results showed that the complete genome of A. ovis was 14 288 bp,encoded 36 genes,containing 12 pro- tein-coding gens （coxl-3 ,nadl-6 ,nad4L,atp6 and cytb）,two tRNA, two rRNA and two non-cod- ing regions. The similarities of the nucleotide sequences between A. ovis and A. lurnbricoides, and A. suurn were 98.7% and 98.2% , respectively. The phylogenetic tree based on sequences of the concatenated amino acids of 12 protein-coding genes indicated the same clade of A. ovis,A, suum, and A. lumbricoides,with a close relationship. Our results suggested that A. ovis,A, lumbricoides and A. suum would represent the same species and provided the fundamental data of classification, evolution,molecular epidemiology and control of A. ovis.